Frequency doubling in LiNbO3 using temperature-dependent QPM
Frequency doubling in LiNbO3 using temperature-dependent QPM
复制标题
使用温度相关的 QPM 在 LiNbO3 中进行倍频
DOI：
10.1088/1464-4258/1/1/008
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发表时间：
1999
影响因子：
2.1
通讯作者：
C. Pedersen
中科院分区：
文献类型：
--
作者：
M. Belmonte;T. Skettrup;C. Pedersen
报道了周期场极化LiNbO_3晶体的温度相关准相位匹配(QPM)在绿光倍频中的应用。与通常的QPM器件不同，这里的基波和二次谐波是正交极化的，因此二次谐波信号对应于非常波。这需要利用非线性张量的D31分量(即与用于普通双折射相位匹配的相同分量)。D31比QPM器件中通常使用的D33分量小，因此效率较低。然而，在我们的几何结构中使用QPM和正交极化波导致了极大的温度可调性，这增加了器件的通用性。此外，在室温和1064 nm的激光波长下，这种几何结构的一阶准相位调制所需的磁畴反转光栅周期较大(350µm)，因此更容易制作。与双折射相位匹配相比，准相位调制技术允许在任何波长进行相位匹配，并消除了走离效应，因为场沿介质主轴之一传播。因此，相互作用路径原则上可以扩展到任意长距离。
We report the application of temperature-dependent quasi-phase matching (QPM) for second harmonic generation of green light using periodically field poled LiNbO3. In contrast to the usual QPM devices, here the fundamental and second harmonic waves are polarized orthogonally so that the second harmonic signal corresponds to the extraordinary wave. This requires the utilization of the d31 component of the nonlinear tensor (i.e. the same component as used for ordinary birefringent phase matching). d31 is smaller than the d33 component usually used in QPM devices and therefore yields a lower efficiency. However, the use of QPM in our geometry with orthogonally polarized waves results in a greatly enhanced temperature tunability, which increases the versatility of the devices. Moreover, the domain inversion grating period required in this geometry for first-order QPM at the Nd laser wavelength 1064 nm and room temperature is relatively large (350 µm), and therefore easier to fabricate. Compared with birefringent phase matching, the QPM technique allows for phase matching at any wavelength and eliminates the walk-off effect since the fields propagates along one of the dielectric principal axes. The interaction path can therefore, in principle, be extended over arbitrarily long distances.